How many crickets to feed my beardie?

Hey guys, I was just wondering, how many crickets should I feed my bearded dragon? He is now around 8 months old and I've had him since he was small. What bothers me, is that I need to go buy 50 crickets, twice per week, which costs 13.8$ per week... Isn't there a cheaper way to feed my meardie ? And when he's an adult, I can't even imagine how much I'll have to pay...